Participants had their fasting blood glucose and insulin levels tested to calculate their baseline insulin resistance and their cognitive functions assessed with a computerised battery of tests to determine their memory, executive function, visual spatial processing and attention.

Diabetes

Follow-up assessments were conducted 15 years later and then again after another five years.

The researchers found that patients in the top quarter for having the highest baseline insulin resistance were at increased risk for poor cognitive performance and accelerated cognitive decline compared to those in the lower quarters.

Lead author Professor David Tanne said: ‘These are exciting findings because they may help to identify a group of individuals at increased risk of cognitive decline and dementia in older age.

‘We know that insulin resistance can be prevented and treated by lifestyle changes and certain insulin-sensitizing drugs. Exercising, maintaining a balanced and healthy diet, and watching your weight will help you prevent insulin resistance and, as a result, protect your brain as you get older.’